Ten years after the fall of the Taliban, with a withdrawal date fixed and economic problems crowding in at home, Afghanistan risks becoming Britain's invisible conflict. But in the days and months ahead the scale of our military effort and sacrifice must be matched by a renewal of our diplomatic effort.

This week representatives of more than 90 countries are expected to attend the Bonn conference – but you would be forgiven for having missed the national debate around Britain's approach.

The prime minister last made a statement on Afghanistan in the House at the start of July and the Foreign Office has yet to set out a detailed position going into these vital talks.

The British people rightly give their unqualified support to our forces in Afghanistan but they are sceptical that politicians have a clear strategy for ending this war.

That is partly a consequence of 10 years of fighting and the heavy price our military personnel and their families have paid. But it does mean there is a heavy responsibility on political leaders to be constantly explaining not just why we are in Afghanistan but what our strategy is for leaving behind a country that does not threaten our security again and does justice to the blood and treasure we have already lost.

Of course big international summits like this tend to focus on broad themes but in truth there is now only a narrow window of opportunity for meaningful action as the US prepares to withdraw most of its combat forces by 2014. So no opportunity should be wasted between now and the Nato summit in Chicago next May.

The Bonn summit should focus on the three pillars needed to build a safer, more stable and more sustainable Afghanistan – continued military pressure, the handover to the Afghan army and a lasting political settlement.

This discrepancy may in part reflect the fact that insurgents are targeting officials and other civilians who threaten their political interests rather than just international forces.

Spectacular attacks, such as the one on Kabul's Intercontinental hotel, may be a sign of the insurgents' strategic weakness but they do have a negative impact on ordinary Afghans' faith in the security infrastructure.

Sustained military pressure is producing results in central Helmand and our special forces are killing and capturing a growing proportion of senior Taliban leadership.

Yet what is the strategy for dealing with this latest increase in violence?

The Afghan army and police combined currently number about 308,000, and are due to reach their peak strength of 352,000 by next November. But their ability to keep control is hampered by figures suggesting that the current proportion of southern Pashtuns in the army is less than 4% while estimates of Pashtuns in the wider population tend range between 40-45%.

There is also an unresolved and increasingly urgent funding problem. The Afghan government will still need at least $10bn (£6.4bn) annually from foreign donors after 2014, $6bn of which will be needed for the Afghan army and police; the United States is already making it clear it will not fund the full amount on its own.

At the same time concerns about central government in Afghanistan remain. Transparency International surveys of local opinion show Afghanistan to be the third most corrupt state in the world, with 60% of those polled saying that corruption had increased in previous years.

Underlying all of this is the third pillar necessary to end the war: an inclusive political settlement, with the tribes in, and al-Qaida out.

Military commanders on the ground tell you that they cannot kill or capture their way out of an insurgency. Battlefield advances on their own are not enough. Work could and should be under way now to try and ensure long-term security guarantees that Afghanistan will not host al-Qaida again. For example, a "status of forces" agreement to regulate any continuing role for international forces should now be under discussion.

The Afghan high peace council established at the London conference in 2010 should continue work to reach a consensus on constitutional arrangements and ensure that women have a proper role in Afghanistan's future. It is likely that Afghanistan's thousands of villages and valleys will need a less centralised system than the present constitution and that is a process that should be explored now.

Progress is possible but big decisions need to be taken quickly – and not just talked about. The military and development efforts continue in the country. But on the timescale laid down for transition to Afghan control, only politics can complete the bridge between where Afghanistan is and where Afghanistan needs to be.

We now have an end date in Afghanistan. It is through urgent diplomatic work at Bonn and beyond that we can also get an end state worthy of the sacrifices endured during the decade-long struggle.